KCNMA1 and glioblastoma: K+ currents of the glioblastoma cell line U-87 MG (N=3, n=5) have a similar current–voltage (I–V) relationship as in primary GBM cells (Fig. 1B) (N=3, n=11); which confirms the suitability of the cell line as a model to study KCa1.1 in GBM.